Suspected Golden State Killer charged for what may have been his first murder in 1975

Joseph James DeAngelo (left), the suspected Golden State Killer, talks with public defender Diane Howard as he appears in court for his arraignment on April 27 in Sacramento, California. DeAngelo, a 72-year-old former police officer, is suspected of killing at least 13 people, raping over 50 women and burglarizing hundreds of homes throughout California in the 1970s and 1980s. (Justin Sullivan/Getty Images)

A man suspected to be the infamous Golden State Killer was charged today for what could have been his very first murder. The murder in question was committed more than four decades ago in 1975, and brings the total number of murders that he is charged with up to 13.

Who was the Golden State Killer?

The Golden State Killer is a moniker given to Joseph James DeAngelo, the suspect behind 120 home burglaries, more than 50 rapes, and 13 murders in California during the 1970s and 80s.

The statute of limitations on rape in California was 10 years until 2016, so prosecutors will focus instead on the murders. The statute of limitations for rape was eliminated in the state in 2016, but the new law only applies to crimes committed after Jan. 1, 2017, and so won't have any practical effect until 2027.

During the initial investigation, the Golden State Killer was known as the East Area Rapist. The term "Golden State Killer" was coined by Michelle McNamara, the late wife of comedian Patton Oswalt and an accomplished writer in her own right. McNamara wrote an exhaustive book detailing the killer's exploits and the efforts of law enforcement to find him.

This book, which was finished by her husband, an investigative journalist, and a researcher who worked with her on the project, was published shortly after her death and just two months before DeAngelo was arrested.

How was this case finally solved?

For decades, this case went cold. Detectives and amateur sleuths alike were at a loss. Then the advent of DNA testing provided new possibilities.

Investigators used DNA recovered from a crime scene to find distant ancestors of the killer through a GEDMatch, a family history website that allows users to upload raw DNA data instead of having to send in spit samples like Ancestry.com or 23andMe. Based on the DNA profile, GEDMatch provided potential living distant relatives of the killer.

Lead investigator Paul Holes then used these relatives to try to build a family tree and figure out where the killer might fit. This search led him to a former cop who had lived near where the killings took place. An item from the man's trash provided the match need to issue a warrant.

On April 25, police arrested the 72-year-old DeAngelo on two counts of murder.

What happened on Monday?

DeAngelo was charged with what may have been the Golden State Killer's first murder: The 1975 shooting of Claude Snelling. Snelling surprised and confronted the killer as he was dragging Snelling's daughter, Elizabeth, out of her bedroom in the middle of the night.

Snelling would die on the way to the hospital, but Elizabeth credits her father's courage with saving her life.

"I would not be here today, I'm sure of it, if it hadn't been for him," she told CBS News.

This attack was initially credited to the "Visalia Ransacker" who committed around 100 burglaries over 18 months in the mid-1970s.

In a news conference on Monday, officials from Tulare County, California, revealed that they had strong evidence to suggest that the Visalia Ransacker and the Golden State Killer were one and the same. Based on this, they filed charges against DeAngelo for Snelling's murder.